University students and researchers working on a
NASA mission orbiting a near-Earth asteroid have made an unexpected detection
of a phenomenon 30 thousand light years away. Last fall, the student-built
Regolith X-Ray Imaging Spectrometer (REXIS) onboard NASA’s OSIRIS-REx
spacecraft detected a newly flaring black hole in the constellation Columba
while making observations off the limb of asteroid Bennu.
This image
shows the X-ray outburst from the black hole MAXI J0637-043, detected by the
REXIS instrument on NASA’s OSIRIS-REx spacecraft. The image was constructed
using data collected by the X-ray spectrometer while REXIS was making
observations of the space around asteroid Bennu on Nov. 11, 2019. The outburst
is visible in the center of the image, and the image is overlaid with the limb
of Bennu (lower right) to illustrate REXIS’s field of view.
Credits:
NASA/Goddard/University of Arizona/MIT/Har
REXIS, a shoebox-sized student
instrument, was designed to measure the X-rays that Bennu emits in response to
incoming solar radiation. X-rays are a form of electromagnetic radiation, like
visible light, but with much higher energy. REXIS is a collaborative experiment
led by students and researchers at MIT and Harvard, who proposed, built, and
operate the instrument.
On Nov. 11, 2019, while the REXIS
instrument was performing detailed science observations of Bennu, it captured
X-rays radiating from a point off the asteroid’s edge. “Our initial checks
showed no previously cataloged object in that position in space,” said Branden
Allen, a Harvard research scientist and student supervisor who first spotted
the source in the REXIS data.
The glowing object turned out to be
a newly flaring black hole X-ray binary – discovered just a week earlier by
Japan’s MAXI telescope – designated MAXI J0637-430. NASA’s Neutron Star
Interior Composition Explorer (NICER) telescope also identified the X-ray blast
a few days later. Both MAXI and NICER operate aboard NASA’s International Space
Station and detected the X-ray event from low Earth orbit. REXIS, on the other
hand, detected the same activity millions of miles from Earth while orbiting
Bennu, the first such outburst ever detected from interplanetary space.
“Detecting this X-ray burst is a
proud moment for the REXIS team. It means our instrument is performing as
expected and to the level required of NASA science instruments,” said Madeline
Lambert, an MIT graduate student who designed the instrument’s command
sequences that serendipitously revealed the black hole.
X-ray blasts, like the one emitted
from the newly discovered black hole, can only be observed from space since
Earth’s protective atmosphere shields our planet from X-rays. These X-ray
emissions occur when a black hole pulls in matter from a normal star that is in
orbit around it. As the matter spirals onto a spinning disk surrounding the
black hole, an enormous amount of energy (primarily in the form of X-rays) is
released in the process.
“We set out to train students how to
build and operate space instruments,” said MIT professor Richard Binzel,
instrument scientist for the REXIS student experiment. “It turns out, the
greatest lesson is to always be open to discovering the unexpected.”
The main purpose of the REXIS
instrument is to prepare the next generation of scientists, engineers, and
project managers in the development and operations of spaceflight hardware.
Nearly 100 undergraduate and graduate students have worked on the REXIS team
since the mission’s inception.
Image & info via APOD
No comments:
Post a Comment